Torque converters, when used in automobiles, comprise only part of the power train from the engine to the driving wheels. A transmission also must be provided to obtain forward, neutral, reverse, and a low speed ratio. A kick-down ratio for passing other vehicles also is desirable. A transmission also is needed with my improved converter but the low speed gear ratio can be dispensed with as an equivalent ratio is obtained in my converter. Another important feature is that the impeller of this converter may be effectively locked to the turbine when the converter would otherwise function as a fluid coupling. The ten percent fuel loss inherent in converters when operating as fluid couplings is thereby eliminated for normal and high speed driving; also the oil cooler necessary with the conventional converter may be dispensed with.